1. Field
Example embodiments provide a method of preparing graphene and a graphene particle manufactured in accordance with this method.
2. Description of the Related Art
Graphene is a conductive material having a two-dimensional honeycomb arrangement of carbon atoms and a thickness of one atom layer.
The graphene forms graphite when three-dimensionally piled, carbon nanotubes when one-dimensionally rolled, and fullerene when zero-dimensionally shaped into a ball, and thus has been regarded as an important model for researching various low-dimensional nano-phenomena.
The graphene is predicted to not only be structurally and chemically very stable but also so conductive that it can transfer electrons 100 times as fast as silicon and flow a current about 100 times as fast as copper.
These predicted characteristics of the graphene have been experimentally proved, since a method of separating graphene from graphite was discovered in 2004, which thrilled scientists all over the world for several years.
The graphene is formed of a relatively light element, carbon, and is easily processed into a one- or two-dimensional nanopattern, which may not only be used to adjust semiconductor-conductor properties, but also be vastly applied to functional devices (e.g., sensors and/or memories) by using various chemical bonds of the carbon.
Accordingly, a technology using the graphene draws a lot of attention, but a method of massively producing the graphene with a relatively low cost, a large area, and reproducibility has not yet been developed.
In general, the graphene may be prepared in five methods. A first method is mechanical or chemical peeling or breaking large graphite into pieces and thus forming a monolayer, but it is difficult to prepare graphene having a large area.
A second method is epitaxy synthesis of raising carbon adsorbed or included in a crystal at a relatively high temperature into graphene on the surface thereof to form graphene having a large area, but has a drawback of needing an expensive substrate device and bringing about relatively insufficient electrical characteristics.
In addition, an organic synthesis method may use tetraphenyl benzene, but has drawbacks of being difficult to produce graphene having a large area and it is expensive.
Lastly, a chemical vapor deposition method synthesizes graphene by depositing a transition metal (Ni or Cu) catalyst layer on a substrate that adsorbs carbon well, reacting the substrate having the catalyst layer with a mixed gas of CH4 and hydrogen at a relatively high temperature (1000° C.) so that carbon in an appropriate amount is melted or adsorbed in the catalyst layer, and then cooling the carbon melted or adsorbed in the catalyst layer on the substrate by using a melting temperature difference between the catalyst and the carbon.
However, this method has a drawback of separating the catalyst layer and the graphene layer with a relatively high cost at a relatively high reaction temperature.
In addition, the method has difficulties in regulating reaction time of methane and hydrogen gas, a cooling rate, concentration of a reaction gas, and/or thickness of a catalyst layer, and continuously performing a process.